(CNN) -- A mass grave unearthed Tuesday in downtown Montgomery, Alabama, is believed to contain bodies from an epidemic of yellow fever that swept the city in the 1870s, police said.

Two buildings from the 1940s were torn down at the site, and maintenance workers grading the land in preparation for the construction of a new building uncovered the remains, said Montgomery police spokesman Maj. Huey Thornton.

The site is adjacent to a cemetery, he said, and "based on the information we have from historical documents kept by the actual cemetery ... it does appear that it may be remains from a yellow fever epidemic in the 1870s."

Officials from the Alabama Archaeological Society and the Alabama Historical Association were at the site and are expected to be able to confirm that, he said.

It was not immediately known how many bodies might be buried at the site, Thornton said, but authorities are reassuring the public there is no cause for concern. The remains are clearly too old to suggest any recent activity, he said.

According to an article posted online by the Mississippi Project of the American Local History Network, an extensive outbreak of yellow fever occurred in 1878, spreading across eight states but particularly affecting Alabama, Louisiana and Mississippi. Some 16,000 people died from the disease that year alone, according to the article.